Fuel Cell, Method and Apparatus for Manufacturing Fuel Cell

ABSTRACT

A fuel cell (stack or a single cell) includes a cell module to which an aging process that progresses initial creep has been applied such that creep during use is reduced compared with a cell module to which the aging process has not been applied. A manufacturing method of a fuel cell (stack or a single cell) includes an aging step for progressing through initial creep by applying at least a compression load to a cell module.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a fuel cell, a method and apparatus ofmanufacturing the fuel cell.

2. Description of the Related Art

Japanese Patent Application Publication No. JP-A-2002-35985 discloses afuel cell stack. This fuel cell stack has an elastic member provided atone end thereof to compensate for changes in tightening load. Inparticular, the gradual loosening or reduction in tightening force,caused by, for example, thermal expansion and contraction, or creep inthe lengthwise direction of the stack. The elastic member may be a discspring, for example, which is able to compensate for changes in thetightening load by adjusting to changes in the lengthwise direction ofthe fuel cell stack that are within the effective stroke range of thedisc spring.

When a tightening load is applied to the fuel cell stack over anextended period of time, however, creep of an adhesive layer betweenseparators of the cell module or the like causes the fuel cell stack tocontract in the direction in which the cell modules are stacked. If acarbon separator is used, creep of the binder resin of the separatoritself may occur. If the extent of contraction exceeds the amount offluctuation in tightening load that can be compensated for by the discspring, it will not be possible to prevent further loosening or decreasein tightening force.

SUMMARY OF THE INVENTION

In view of the above, the invention provides a fuel cell capable ofsuppressing fluctuations in the length of a fuel cell stack or thicknessof a single cell, a method of manufacturing such a fuel cell, and anapparatus for manufacturing the fuel cell.

A fuel cell according to a first example embodiment of the inventionincludes a cell module that has been subjected to an aging process thatprogresses initial creep in the cell module so that dimensional changesdue to creep can be minimized.

According to the foregoing first aspect, an aging process is applied tothe cell module before it is used so that creep of the stack during useof the fuel cell can be reduced. As a result, the necessary tighteningload of the fuel cell stack can be maintained throughout the targetlifetime of the cell module. This is because creep initially progressesrapidly (e.g., primary creep) but then slows down afterwards (e.g.,steady-state creep). Thus, inducing creep through the initial stage maytherefore be considered a rational approach because the process ofprogressing through initial creep can be completed relatively quickly.

Also, a manufacturing method of a fuel cell according to a second aspectof the invention includes an aging step for progressing through initialcreep by applying at least a compression load to the cell module.According to this second aspect, providing an aging step for progressingthrough initial creep by applying at least a compression load to a cellmodule enables creep of the stack during use of the fuel cell to bereduced. As a result, the necessary tightening load of the fuel cellstack can be maintained throughout the target lifetime of the cellmodule. As described in the preceding paragraph, the process ofprogressing through initial creep can be completed quickly, asdeformation during primary creep occurs rapidly before stabilizing.

In the aging step, the cell module may be subjected to a thermal load inaddition to the compression load. In addition, a compression load mayalso be applied for a predetermined period of time that is shorter thanthe target lifetime of the product. By applying a thermal load inaddition to the compression load in the aging step, it is possible toboth accelerate the progression of creep more so than when only thecompression load is applied, and reduce creep during actual use in whichthere is a thermal load. In addition, it is possible to finish aging ina shorter period of time.

In this case, the predetermined period of time may be determined basedon (i) the correlative relationship between an amount of change in thethickness of the cell module and the cumulative time over which thecompressed load is applied to the cell module; (ii) the lower limit ofthe effective stroke of the elastic body provided in the stack; or (iii)the thermal contraction amount of the stack.

The thermal load may be applied by running a heated fluid through afluid flow path of the cell module. Pressure may be applied to theheated fluid. Applying the thermal load by running a heated fluidthrough a fluid flow path of the cell module enables the thermal load tobe applied easily, as well as in a state close to the state in which thecell module is actually used. Further, applying pressure to the heatedfluid is effective for accelerating creep of the separator when theseparator is a carbon separator.

The manufacturing method according to the second aspect may also includean aging step for progressing through initial creep by applying at leasta compression load to a cell module after stacking, and an additionaltightening step for additionally tightening the fuel cell stack afterthe aging step. The manufacturing method may also include an aging stepfor progressing through initial creep by applying at least a compressionload to a cell module before stacking, and an incorporating step forincorporating the cell module in a stack after the initial creep hasbeen progressed.

A third aspect of the invention relates to an apparatus for assembling afuel cell in accordance with the second aspect of the invention. Theapparatus performs the method of assembly, particularly the agingprocess, automatically.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and further objects, features and advantages of theinvention will become apparent from the following description ofpreferred embodiments with reference to the accompanying drawings,wherein like numerals are used to represent like elements and wherein:

FIG. 1 is a flowchart of a manufacturing method of a fuel cell accordingto a first example embodiment of the invention;

FIG. 2 is a flowchart of a manufacturing method of a fuel cell accordingto a second example embodiment of the invention;

FIG. 3 is a graph illustrating a characteristic (creep+thermalcontraction amount) versus (operating time) of the fuel cell and themanufacturing method thereof according to the first and second exampleembodiments of the invention;

FIG. 4 is a side view of the fuel cell according to the first and secondexample embodiments of the invention;

FIG. 5 is an enlarged sectional view of a portion of the fuel cellaccording to the first and second example embodiments of the invention;

FIG. 6 is a front view of a cell incorporated into the fuel cellaccording to the first and second example embodiments of the invention;and

FIG. 7 is a characteristic graph of load versus displacement of anelastic body incorporated into the fuel cell according to the first andsecond example embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a fuel cell, which may be either a fuel cell stack or asingle cell, and a manufacturing method thereof according to theinvention will be described with reference to FIGS. 1 to 7.

FIG. 1 illustrates a fuel cell and a manufacturing method thereofaccording to a first example embodiment of the invention. FIG. 2illustrates a fuel cell and a manufacturing method thereof according toa second example embodiment of the invention. FIGS. 3 to 7 can beapplied to both the first and second example embodiments of theinvention.

Like reference numerals will be used in both the first and secondexample embodiments of the invention to represent common or similarparts in the first and second embodiments of the invention.

First, a fuel cell (either a fuel cell or a single cell) and amanufacturing method thereof which are common or similar in the firstand second example embodiments of the invention will be described withreference to FIGS. 1, 3, and 4 to 7.

The fuel cell that is the object of the fuel cell and manufacturingmethod thereof according to the invention is a proton-exchange membrane(PEM) fuel cell, for example. This fuel cell is mounted, for example, ina fuel cell vehicle, but may also be used in something other than avehicle.

As shown in FIGS. 4 to 6, the PEM fuel cell 10 is formed of unit fuelcells (also called “unit cells,” “single cells,” or simply “cells”) inwhich a membrane-electrode assembly (MEA) 19 and a separator 18 arestacked together.

This membrane-electrode assembly includes an electrolyte membrane (alsoreferred to as “electrolyte”) 11 which is an ion-exchange membrane, anelectrode (anode) 14 which is a catalyst layer arranged on one surfaceof the electrolyte membrane 11, and an electrode (cathode) 17 which is acatalyst layer arranged on the other surface of the electrolyte membrane11. A diffusion layer 13 is provided on the anode side between themembrane-electrode assembly 19 and the separator 18, and anotherdiffusion layer 16 is provided on the cathode side between themembrane-electrode assembly 19 and the separator 18. The separator 18includes an anode side separator and a cathode side separator. A fuelgas flow path 27 for supplying a fuel gas (such as hydrogen) to theanode 14 is formed in the surface of the anode side separator 18 thatcontacts the diffusion layer 13, and an oxidizing gas flow path 28 forsupplying an oxidizing gas (such as oxygen, normally air) to the cathode17 is formed in the surface of the cathode side separator 18 thatcontacts the diffusion layer 16. Also, flow paths 26 for supplying acooling medium are formed in the surfaces of the separators 18 oppositethe surfaces that contact the diffusion layers 13 and 16.

A fuel cell stack 23 includes a plurality of cell modules, each of whichincludes at least one cell 10 (in a case where there is one cell to onemodule, the cell and the module are the same), that are stacked togetherto form a cell-stacked body. The cell-stacked body is sandwiched betweenterminals 20, insulators 21, and end plates 22 at both ends, in the cellstacking direction. The end plates 22 on both ends are fixed by nuts andbolts 25 to a tightening member 24 (such as a tension plate) whichextends in the cell stacking direction on the outside of thecell-stacked body. A stack tightening load is applied in the cellstacking direction to the cell-stacked body.

An elastic body 35, such as, for example, a disc spring 35, is providedbetween the end plate 22 at one end of the fuel cell stack 23 and apressure plate 34 to the inside of that end plate 22, and applies thetightening load to the stack. Thus, even if the length of thecell-stacked body fluctuates due to creep or thermal expansion andcontraction or the like, that fluctuation is absorbed within the elasticdeformation range of the elastic body 35 so that the tightening loaddoes not change significantly. The initial value of the stack tighteningload may be adjusted by, for example, rotating an adjustment screw 36,which is screwed into a hole provided in the end plate 22, around itsaxis and adjusting its position in the cell stacking direction.

On the anode 14 side of each cell 10, an ionic reaction takes placewhich splits the hydrogen into hydrogen ions (protons) and electrons.The hydrogen ions move through the electrolyte membrane 11 to thecathode side. Meanwhile, on the cathode 17 side of each cell 10, oxygen,the hydrogen ions, and the electrons (the electrons produced at theanode of the adjacent MEA pass through the separator, or the electrodesproduced at the anode of the cell on one end in the cell stackingdirection pass through an outside circuit and arrive at the cathode ofthe cell on the other side) combine in a reaction to produce water. Thisreaction is as follows.

Anode side: H₂—2H⁺+2e ⁻

Cathode side: 2H⁺2e ⁻+(½)O₂→H₂O

The separator 18 is a carbon separator, a metal separator, a metalseparator that is combined with a resin frame, or a conductive resinseparator.

The separator 18 includes, near its edge portion, an intake-side fuelgas manifold 30 a, an exit-side fuel gas manifold 30 b, an intake-sideoxidizing gas manifold 31 a, an exit-side oxidizing gas manifold 31 b,an intake-side coolant manifold 29 a, and an exit-side coolant manifold29 b. The fuel gas flow path 27 is formed in the surface of the anodeside separator 18 that faces the diffusion layer 13. Similarly, theoxidizing gas flow path 28 is formed in the surface of the cathode sideseparator 18 that faces the diffusion layer 16. The coolant flow path 26is formed in the surfaces of the separator 18 that are opposite thesides facing the diffusion layers.

The fuel gas flows from the intake-side fuel gas manifold 30 a into thefuel gas flow path 27 and then out the exit-side fuel gas manifold 30 b.

Similarly, the oxidizing gas flows from the intake-side oxidizing gasmanifold 31 a into the oxidizing gas flow path 28 and then out theexit-side oxidizing gas manifold 31 b.

Also, the coolant flows from the intake-side coolant manifold 29 a intothe coolant flow path 26, and then out the exit-side coolant manifold 29b.

An adhesive layer 33 provides a seal around the fluid flow paths betweenseparators or between the separator and the membrane of the cell 10. Agasket 32 or an adhesive is used to provide a seal between cell modules.

Creep occurs in the adhesive layer 33 and the separator 18, when theseparator 18 is a carbon separator) when a stack tightening load isapplied to the cell 10, as well as when a stack tightening load and athermal load (an operating temperature of approximately 80 degreesCelsius) are applied to the cell 10, such as when the fuel cell isoperating. As shown by line A in FIG. 3, the amount of deformation dueto creep increases as the total operating time of the fuel cell stack 23increases.

Creep of the cell-stacked body of the fuel cell stack 23 is not aproblem as long as the amount is within the limits of absorption byelastic deformation of the elastic member 35 provided at one end of thefuel cell stack 23. If that amount of creep exceeds the limit ofabsorption by elastic deformation of the elastic member 35 (i.e., if itexceeds the effective stroke lower limit S of the disc spring 35 in FIG.3), the electrical resistance between each cell 10 increases, as well asthe electrical resistance between the separator 18 and the diffusionlayers 13 and 16 in the cell 10. This results in a decrease in fuel celloutput and the likelihood of leaking fluid is increased.

To reduce the chances of this problem occurring, the fuel cell (thestack 23 or the single cell 10) according to one example embodiment ofthe invention is a fuel cell (the stack 23 or the single cell 10) whichincludes a cell module is subjected to which an aging process thatprogresses initial creep before the cell module is incorporated into thefuel cell. As a result, creep over the useful life of the cell module isreduced compared with a cell module to which the aging process has notbeen applied.

Also, a manufacturing method of the fuel cell (the stack 23 or thesingle cell 10) according to one example embodiment of the invention isa manufacturing method of the fuel cell (the stack 23 or the single cell10) which includes an aging step for progressing through initial creepby applying at least a compression load to a cell module before the cellmodule is incorporated into the fuel cell.

Aging may be applied to the stack 23 as a whole or to each single cell10 separately.

The term aging refers to progressing through initial creep of the cellmodule by applying at least a compression load (either only acompression load, or both a compression load and a thermal load) for apredetermined period of time H to the cell module (either before orafter stacking of the cell module). The compression load corresponds toa stack tightening load. The thermal load is a load applied to the cellmodule by increasing the temperature to, for example, the fuel celloperating temperature or a temperature that the cell can withstand whichis above the fuel cell operating temperature.

Also, the predetermined period of time H may be a period of timedetermined based on the correlative relationship between an amount ofchange (creep+thermal compression amount) in the thickness of the cellmodule and the cumulative time h for which the compression load isapplied to the cell module, as shown in FIG. 3.

The predetermined period of time H may also be a period of timedetermined based on an effective stroke lower limit of the elastic body(the disc spring in the illustrated example) of the stack 23.

The predetermined period of time H may also be a period of timedetermined based on the thermal compression amount of the stack 23 (orthe cell module).

The predetermined period of time H can be obtained as shown in the graphof (creep+thermal compression amount) versus operating time h in FIG. 3,for example. That is, in the graph, a broken line B which shiftsparallel to line A is drawn below line A. The distance between the twolines is a value equal to or greater than an amount E by which line Aovershoots the effective stroke lower limit S (such as 4 mm with thestack) of the disc spring 35 at the target life L (for example, 5years). A vertical line is then drawn which extends down from a point C,where the broken line B intersects with a thermal compression amount T(such as 1 mm with the stack), to the operating time axis. Thepredetermined period of time H can then be obtained as a value H on theoperating time axis at a point D where this vertical line intersectswith the operating time axis. The predetermined period of time H is, forexample, between 20 and 50 hours, and more specifically, between 30 and40 hours, i.e., it is short compared with the target life L (forexample, 5 years).

Further, in the aging process, the thermal load can be applied to thecell module by running a heated fluid (hot water or gas heated toapproximately 80 to 100 degrees Celsius) through the fluid flow paths26, 27, and 28 of the cell module. Pressure may also be applied to theheated fluid. Applying both a compression load and a thermal load makeit possible to progress creep in a short period of time.

More specifically, the following mode may also be employed.

(A) Creep is progressed by applying a thermal load to the cell module bycirculating water that has been heated to the highest operatingtemperature through the stack coolant line. The water may be pressurizedsuch that a pressure load is also applied at this time. Also, nitrogenand air may be supplied into the gas lines and pressurized. The pressureload is effective for progressing through initial creep (creep of aresin binder of a carbon separator) of a separator by applying pressureto the separator.

(B) In addition to the method described above, a method of applyingtemperature and compression loads by running hot water through both thecoolant and gas lines may also be employed. Another method which may beemployed is to apply temperature and compression loads to the cellmodule by conversely running a heated gas such as nitrogen through thecoolant and gas lines.

(C) The fuel cell may be operated to generate power and temperature andcompression loads applied to each cell/module at that time. Whenoperating the fuel cell to generate power, a voltage increase effect (aconditioning effect) can also be expected, in addition to progressingthrough initial creep, due to catalyst activation and an appropriateamount of moisture being applied to the electrolyte membrane.

(D) A method of applying temperature and compression loads by placingthe stack in a thermostatic chamber or furnace may also be applied.

Next, the operation and effects of the fuel cell (the stack 23 or thesingle cell 10) and the manufacturing method thereof according to thefirst and second example embodiments will be described.

With the foregoing fuel cell (the stack 23 or the single cell 10), anaging process is applied to the cell module before it is used. As aresult, creep of the fuel cell (the stack 23 or the single cell 10)while it is being used can be reduced.

Also, the foregoing manufacturing method of the fuel cell (the stack 23or the single cell 10) includes an aging step for progressing throughinitial creep by applying at least a compression load to a cell module.As a result, creep of the fuel cell (the stack 23 or the single cell 10)while it is being used can be reduced.

As a result, in both the case of the fuel cell (the stack 23 or thesingle cell 10) and the case of the manufacturing method of the fuelcell (the stack 23 or the single cell 10), the necessary tightening loadon the fuel cell stack 23 is able to always be maintained within thetarget life L. That is, referring to FIG. 3, the operating time h iswithin the target life L and the broken line B, which indicates thecharacteristic of a fuel cell that includes the cell modules to whichthe aging step has been applied, is below the effective stroke lowerlimit S of the disc spring, and the creep+thermal compression amount isalways within the effective stroke S of the disc spring. Thus, even ifcreep of the stack progresses, the change in stack length can beabsorbed by the disc spring 35 so the tightening force can be keptsubstantially constant. In this case, the load-to-stroke characteristicof the disc spring 35 is one which has a generally flat portion F in themiddle, as shown in FIG. 7. Therefore, the stack tightening force can bekept substantially constant by using this generally flat portion F.

Also in FIG. 3, as is evident from the solid line A indicating thecharacteristic of related art, creep progresses rapidly early on andthen decreases over time. Accordingly, inducing creep in the initialstage may be considered a rational approach because it can be done witha process that takes only as much time as it takes for creep to progressat that stage, i.e., it is a quick process.

Also, in addition to the compression load, a thermal load may also beapplied to the cell module in the aging step. As a result, the progressof creep can be accelerated compared with a case in which only acompression load is applied. In addition, creep during actual usage ofthe fuel cell in which there is a thermal load can be reduced.

In addition, aging is performed by applying at least a compression loadto the cell module for a predetermined period of time H (thispredetermined period of time is short compared to the target life). As aresult, aging can be done quickly.

In this case, the predetermined period of time H is a period of timethat can be obtained from FIG. 3 or the like.

Also, the thermal load is applied by running a heated fluid through thefluid flow paths 26, 27, and 28 of the cell module. As a result, thethermal load (temperature load) can be applied both easily, as well asin a state close to the state in which the cell module is actually used.

Further, pressure is applied to the heated fluid, which is effective foraccelerating creep of the separator 18 when the separator 18 is a carbonseparator.

Next, the structure, operation, and effects of portions specific to eachexample embodiment of the invention will be described.

First Example Embodiment FIG. 1

The fuel cell (the stack 23 or the single cell 10) according to thefirst example embodiment of the invention is manufactured according toFIG. 1. Also, the manufacturing method of the fuel cell (the stack 23 orthe single cell 10) according to the first example embodiment of theinvention is a manufacturing method according to the steps shown inFIG. 1. The manufacturing method of a fuel cell (the stack 23 or thesingle cell 10) according to the first example embodiment of theinvention is a manufacturing method of a fuel cell, which includes anaging step 103 for progressing through initial creep by applying atleast a compression load to a cell module after stacking, and anadditional tightening step 104 for additionally tightening the fuel cellstack 23 after the aging step 103.

In the fuel cell (the stack 23 or the single cell 10) and themanufacturing method thereof according to the first example embodimentof the invention, as shown in FIG. 1, the cell modules are laminated andstacked in step 101, and tightened in step 102. An aging process is thenapplied to the (cell module of the) stack 23 in step 103, after whichthe stack 23 is then additionally tightened in step 104. Then in step105 a finished goods inspection is performed on the stack which is thenshipped in step 106.

Regarding the operation and effects of the first example embodiment, inFIG. 3, after tightening, aging is performed in step 103 for apredetermined period of time H, during which creep progresses from thestarting point to point G. Then in step 104 additional tightening of anamount corresponding to E is performed to bring the creep from point Gto point C. Then with use, the creep increases from point C along thebroken line B. Even when the target life in operating time h is reached,however, the creep still remains within the disc spring effective strokeS.

As a result, the necessary tightening load of the fuel cell stack 23 isalways maintained within the target life.

Also, aging can be applied to the cell module after stacking, whichobviates the need to disassemble and then reassemble the stack after theaging step.

Second Example Embodiment FIG. 2

The fuel cell (the stack 23 or the single cell 10) according to thesecond example embodiment of the invention is manufactured according toFIG. 2. Also, the manufacturing method of the fuel cell (the stack 23 orthe single cell 10) according to the second example embodiment of theinvention is a manufacturing method according to the steps shown in FIG.2. The manufacturing method of a fuel cell (the stack 23 or the singlecell 10) according to the second example embodiment of the inventionincludes an aging step for progressing through initial creep by applyingat least a compression load to a cell module before stacking, and anincorporating step for incorporating the cell module into the stackafter the initial creep has been progressed.

With the fuel cell (the stack 23 or the single cell 10) and themanufacturing method thereof according to the second example embodiment,as shown in FIG. 2, cell modules are supplied in step 201. The cellmodule is set, either individually or with other cell modules, in a jig(between an upper jig and a lower jig) in step 202. In step 203, the jigis then tightened and sealed with the cell module. In step 204, an agingprocess is applied to the cell module. Then in step 205, the cell moduleis extracted from the jig and separated into single cell modules (in acase where a plurality are provided) which are then incorporated intothe stack 23 in step 206 or step 207. In step 206, the cell modules areshipped for use as replacements when a defective cell module has beendetected in an inspection such as that in step 105 of FIG. 1. In step207, the cell modules are shipped to provide a cell module supply forservice stations and the like. In the method illustrated in FIG. 2 thereis no additional tightening step 104 of the stack, which is differentfrom the method illustrated in FIG. 1.

Regarding the operation and effects of the second example embodiment, inFIG. 3, creep increases from the starting point to point G at the stagewhere the cell modules are mounted in the jig and aging is applied. Thenat the stage where the cell modules are separated and incorporated intoa stack, creep decreases from point G to point C. The cell modules arethen used, during which creep increases from point C along the brokenline B. Even when the target life in operating time h is reached,however, the creep still remains within the disc spring effective strokeS.

As a result, the required tightening load of the fuel cell stack 23 canbe maintained throughout the target lifetime of the cell module.

The aging process may also be applied to the cell module beforeincorporation into the stack, which makes it possible to use the cellmodule for replacement in the first example embodiment, or for supply ata service station.

The apparatus includes assemblies for implementing the key steps of themethod of the second aspect. In particular, assemblies are provided forcompressing and heating the cell module in order to progress throughinitial creep. The apparatus also provides a tightening assembly thattightens the stacked cell module after the aging step is completed. Theapparatus may also provide a jig in which a cell module or plurality ofcell modules may be set.

1. A fuel cell comprising: a cell module to which an aging process thatprogresses initial creep has been applied such that creep during use isreduced compared with a cell module to which the aging process has notbeen applied.
 2. A manufacturing method of a fuel cell, comprising: anaging step for progressing through initial creep by applying acompression load to a cell module.
 3. The manufacturing method accordingto claim 2, wherein: a thermal load is also applied, in addition to thecompression load, to the cell module in the aging step.
 4. Themanufacturing method according to claim 2, wherein: the compression loadis applied for a predetermined period of time to the cell module in theaging step.
 5. The manufacturing method according to claim 4, wherein:the predetermined period of time is determined based on a correlativerelationship between an amount of change in the thickness of the cellmodule and a cumulative time over which the compressed load is appliedto the cell module.
 6. The manufacturing method according to claim 4,wherein: the predetermined period of time is determined based on aneffective stroke lower limit of an elastic body that applies an elasticforce to a stacked body of the cell module.
 7. The manufacturing methodaccording to claim 4, wherein: the predetermined period of time isdetermined based on a thermal contraction amount of an entire stackedbody of the cell module.
 8. The manufacturing method according to claim3, wherein: the thermal load is applied by running a heated fluidthrough a fluid flow path in the cell module.
 9. The manufacturingmethod according to claim 8, wherein: the heated fluid is pressurized.10. The manufacturing method according to claim 2, wherein: initialcreep is progressed in the aging step by applying the compression loadto the cell module after stacking the cell module, further comprising: astep for additionally tightening the stacked cell module after the agingstep.
 11. The manufacturing method according to claim 2, wherein:initial creep is progressed in the aging step by applying thecompression load to the cell module before stacking the cell module,further comprising: a step for incorporating the cell module after theinitial creep has been progressed as a portion of a cell module stackedbody.
 12. A fuel cell manufactured by the manufacturing method accordingto claim
 2. 13. A fuel cell comprising: a tightening member; and aplurality of cell modules which are tightened in a stacked state by thetightening member, wherein the cell modules are cell modules in whichcreep has been progressed a predetermined amount before tightening bythe tightening member.
 14. The fuel cell according to claim 13, wherein:each cell module is a structure which sandwiches a solid electrolytemembrane by a pair of separator.
 15. The fuel cell according to claim13, further comprising: an elastic body that applies an elastic force asa tightening load to the cell modules.
 16. An apparatus formanufacturing a fuel cell characterized by comprising: a compressionassembly that applies a compression load to a cell module, wherebyinitial creep in the cell module is progressed.
 17. The apparatus formanufacturing a fuel cell according to claim 16, further comprising: aheating assembly that applies a thermal load to the cell module.
 18. Theapparatus for manufacturing a fuel cell according to claim 16, whereinthe compression assembly applies the compression load to the cell modulefor a predetermined period of time.
 19. The apparatus for manufacturinga fuel cell according to claim 17, wherein the heating assembly heats afluid to an appropriate temperature, and runs the heated fluid throughfluid flow paths within the cell module.
 20. The apparatus formanufacturing a fuel cell according to claim 19, wherein the heatedfluid is pressurized.
 21. The apparatus for manufacturing a fuel cellaccording to claim 16, wherein the cell module is stacked before thecompression assembly applies the compression load to the cell module.22. The apparatus for manufacturing a fuel cell according to claim 21,further comprising: a tightening assembly that further tightens thestacked cell module by tightening the cell module with an increasedtightening force after initial creep in the cell module is progressed.